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First observation of Navilithus altivelum in the Gulf ofMexico
Jarrett Cruz, Sherwood WiseEarth, Ocean and Atmospheric Science Florida State University P.O. Box 3064520 Tallahassee, Florida Jwc09e@my.fsu.edu

Jeremy R. Young
Dept. of Earth Sciences, University College London, Gower Street, London WC1E 6BT

Abstract: 7KH FRFFROLWKRSKRUH Navilithus altivelum ZDV ÀUVW GHVFULEHG E\ <RXQJ DQG $QGUXOHLW   IURPsamples collected in the Eastern Indian Ocean. There have been no other published observations of this species or it’spreferential niche within the photic zone. It has recently been observed, however, in Gulf of Mexico (GOM) during
September, 2013 from sampling on the RV Bellows during the Deep-C GOM sampling project. We present some variaWLRQLQLWVSUHYLRXVO\REVHUYHGHFRORJLFDOSUHIHUHQFHDQGDLGLQGHÀQLQJQLFKHSDUDPHWHUVZLWKWKHLQLWLDOGHVFULSWLRQusing in-situ CTD measurements as well as other coccolithophore species found alongside the Navilithus altivelumcells.
Introduction
Navilithus altivelum is a trimorphic deep photic coccolithophore species described by Young & Andruleit(2006) from samples found below the thermocline in theIndian Ocean and not recorded since. The three distinct
W\SHV RI FRFFROLWKV LW SURGXFHV DUH FLUFXPÁDJHOODU VDLOcoccoliths, moderately elevated coccoliths, and bodycoccoliths with a basal structure similar to that of otherspecies in the narrow-rimmed placoliths group of Younget al. (2003). For a more detailed description, see Youngand Andruleit (2006). Here we discuss the preferential
niche of Navilithus altivelum within the Gulf of Mexico
XVLQJ ZDWHUFKHPLVWU\ SURÀOHV IURP &7' UHDGLQJV WKDW
give temperature, salinity, and chlorophyll data for theobserved Navilithus altivelum coccospheres. The samples
were taken from station P7 off the Pensacola coast 40
miles from shore (29.75, -87.25) (Figure 1).

tive species-cell counts were recorded in 210 SEM frames
DW  ; PDJQLÀFDWLRQ DW D ZRUNLQJ GLVWDQFH RI DERXWPP 7KLV PHWKRG SURYLGHG HVWLPDWLRQV RI WKH ÀOWHUarea examined (Bown & Young 1998; Winter et al., 1994).
&RFFROLWKRSKRUHVZHUHLGHQWLÀHGXVLQJV\VWHPDWLFGHÀQLtions primarily from Winter and Siesser (1994), Young etal. (2003) and Young and Andruleit (2006).

Results - Species Assemblage and N.
altivelum
Navilithus altivelum coccospheres were observed in only
sample, collected from 50m depth at station P7 (29.75°N,87.25°W) on 14th September 2013. By comparison )ORULsphaera profunda was found in 56 of the 283 samples
studied. Fifteen coccospheres of Navilithus were recordedin this sample which gives a calculated abundance of 9100
cells/liter. The morphology of these was essentially identical to those described by Young & Andruleit (2006) withMaterial and Methods
trimorphic coccospheres consisting of numerous short
Sampling has taken place every 2-4 months over theshort-spined body coccoliths, a few moderately elevatedpast four years along a North-South transect as part ofFRFFROLWKVDQGDJURXSRIWDOOFLUFXPÁDJHOODUVDLOFRFFRthe Deep-C project (http://deep-c.org). On station weliths (Fig 2). The number of coccoliths per coccosphere,
FROOHFWHGDSURÀOHGRZQWRPDWWKHORZHUOLPLWVWR
the arrangement of the different lith types on the coccothe photic zone. Samples were taken via Niskin-bottles
attached to a rosette. The
samples were extracted
from 1-3 liters of waterusing 44-mm diameter
SRO\FDUERQDWHÀOWHUVZLWK0.6 µm pores and vacuumÀOWUDWLRQ7KH ÀOWHUV ZHUH RYHQdried and stored in air
tightcontainers
forprocessing in the lab. The
ÀOWHUVZHUHWKHQPRXQWHGon aluminum stubs andsputter-coated with goldpalladium for study in ascanning electron microscope (SEM). Quantita- Figure 1. Map showing the study site in the Gulf of Mexico, inset is location map also showing the samplingtransect.

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Figure 2. SEM images of Navilithus altivelum, all from sample P7-50m sept 2013. 1. Coccosphere; 2 Body coccoliths; 3 - moderately elevated
FRFFROLWKV&LUFXPÁDJHOODUFRFFROLWKVZLWKVDLOOLNHVSLQHVFigure 3. P7 50m depth: cells per liter counts.

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29sphere, their size, and detailed morphology are all essentially identical to that of the type material.
The N. altivelum specimens from station P7 in theGOM occurred in the lower part of the thermocline,
below the deep chlorophyll maximum (Figure 4). The
water temperature in the sample where the coccospheres
were observed was 22.1 °C., and salinity level was 36.44
PSU. Emiliania huxleyi and Gephyrocapsa oceanica werepresent throughout the entire water column at station P7with E. huxleyi present in major abundances within thesurface waters. The surface waters also contained CalcioSDSSXV ULJLGXV $OJLURVSKDHUD UREXVWD and Ophiasterformosus. At the 50-meter depth (Figure 3) where Navilithus altivelum was present, )ORULVSKDHUDSURIXQGDand*ODGLROLWKXVÁDEHOODWXV were also present. Deeper waters
contained )ORULVSKDHUDSURIXQGDand *ODGLROLWKXVÁDEHOlatus, as well as Calcidiscus leptoporus and 8PEHOORVphaera irregularis specimens which had probably sunkfrom surface waters.
Discussion
The species N. altivelum appears to occur in a similar
position in the water column in the GOM as described byYoung and Andruleit (2006) in the Indian Ocean. In bothcases it occurs in the lower part of the thermocline below
a well-developed deep chlorophyll maximum. It occurs
with DCM species such as *ODGLROLWKXV ÁDEHOODWXV and)ORULVSKDHUDSURIXQGD but does not extend as deep as theydo. These observations and the absence of any records
from the more intensively studied surface waters suggestthat this species is a true deep-photic obligate, living inthe zone of enhanced nutrients but low light below thedeep chlorophyll maximum (Nutrient data was not available for either our sampling or that of Young & Andruleit(2006) but high nutrient levels can be inferred from theZDWUSURÀOHFKDUDFWHUVLWLFV ,QWHUPVRIVLPSOHSK\VLFRchemical parameters, however, the sampled environment
are strikingly different; the Indian Ocean specimens
were found at 100-130 m, 10-12 °C and 34.7-34.9 psuin contrast to the Gulf of Mexico specimens which werefound at 50m, 22°C and 36.4 psu. Clearly the distributionof the species is not closely tied to these parameters. This
rare nannoplankton species Navilithus altivelum is also
an excellent example of how elusive and diverse these
deep-photic oligotrophic species can be. First observed in
the Indian Ocean in 2006 and subsequently observed half
way around the globe in the Gulf of Mexico in 2013, one
could assume Navilithus altivelum is more widely distributed than presently known. This raises the question as tohow diverse and widespread such deep-photic species areand how many more undiscovered nannoplankton taxa
are out there.

Figure 4. Temperature, salinity and chlorophyll data for Station P7, Sept2013. Sampling depths indicated by squares on vertical axis.

Acknowledgments
This research was made possible by a grant from BP/
The Gulf of Mexico Research Initiative to the Deep-C
Consortium (#SA 12-12, GoMRI-008). SEM facilities
were provided by the Florida State University physics
department, the Florida Geological Survey and Valdosta
State University. Some pictures were also provided byDr. Jim Nienow from VSU. We also very grateful for theconstructive comments of Dr Karl-Heinz Baumann andmaria Triantaphyllou.
References
Bown, P.R. & Young, J.R. 1998. Techniques. In: P. R.
Bown (Ed.), Calcareous nannofossil biostratigraphy.
British Micropalaeontological Society Publication
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Winter, A., Jordan, R.W. & Roth, P.H. 1994. Biogeography of living coccolithophores in ocean waters. In:A. Winter & W. G. Siesser (Eds.), Coccolithophores.
Cambridge University Press: 161-177.
Winter, A. & Siesser, W.G. 1994. Atlas of living coccolithophores. In: A. Winter & W. G. Siesser (Eds.), Coccolithophores. Cambridge University Press: 107-159.
Young, J.R. & Andruleit, H. 2006. Navilithus altivelum: aremarkable new genus and species of deep photic coccolithophores. Journal of Micropalaeontology, 25(2):141-152.
Young, J.R., Geisen, M., Cros, L., Kleijne, A., Probert, I.
& Ostergaard, J.B. 2003. A guide to extant coccolithophore taxonomy. Journal of Nannoplankton Research,Special Issue, 1: 1-132.